1366 - Incorrect integer value: '' for column 'customer_id' at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', '0fb30ea4222105c09dfb52c6fa5755b7', '3.145.59.187', '1714018202', '1714018202', '/shop_content.php/coID/7/content/Kontakt')

[XT SQL Error]